Spacer assembly

ABSTRACT

A self-aligning spacer assembly includes a pair of sleeves having end faces held in mutually abutting relationship by a resilient collar. One of the abutting end faces has a convex spherical shape and the other is conical to provide substantial line contact between the faces. One of the sleeves has an internal diameter such that it fits snugly on a shaft or arbor on which the spacer assembly is mounted, an the internal diameter of the other sleeve is slightly greater so that it can rock on the arbor to a limited extent relative to the other sleeve.

United States Patent Mitchell 1 May 16, 1972 [54] SPACER ASSEMBLY [72] Inventor: Wallace F. Mitchell, Arlington Heights, 111.

[73] Assignee: Ammco Tools, Inc., North Chicago, Ill.

[22] Filed: Aug. 24, 1970 [21] Appl. No.: 66,530

[ 5 6] References Cited UNITED'STATES PATENTS 2/1942 Pavleckaet al ..279/16 7/1920 Fuller 2,334,606 11/1943 Castiglia.... ..279/2 UX 2,426,219 8/1947 Jackson.... ..287/53 2,732,213 1/1956 Drew ..279/2 2,956,826 10/1960 Nord ..287/52.06 X 3,039,645 6/1962 Castiglia ..85/50 R X FOREIGN PATENTS OR APPLlCATlONS 864,340 1/1953 Germany ..85/50 R 814,988 9/ l 951 Germany ..287/52.07

Primary Examiner-Andrew V. Kundrat Att0rneyFidler, Patnaude & Lazo [57] ABSTRACT A selfaligning spacer assembly includes a pair of sleeves having end faces held in mutually abutting relationship by a resilient collar. One of the abutting end faces has a convex spherical shape and the other is conical to provide substantial line contact between the faces. One of the sleeves has an internal diameter such that it fits snugly on a shaft or arbor on which the spacer assembly is mounted, an the internal diameter of the other sleeve is slightly greater so that it can rock on the arbor to a limited extent relative to the other sleeve.

5 Claims, 3 Drawing Figures 1 SPACER ASSEMBLY The present invention generally relates to a spacer assembly for mounting on a rodor shaft, and it relates more particularly to such an assembly for spacing two members mounted on a rod or shaft and whose opposing faces are not precisely coplanar.

In order to machine planar faces on rotors such as brake discs, it is the usual practice to mount such rotors on the arbor of a lathe between a pair of adapters designed to mate with the hub portion of the particular rotor. In the resurfacing of brake discs, these adapters are generally designed to mate with the conical surfaces of the outer bearing races which are fixedly mounted within the hub of the brake disc. The adapters fit snugly on the arbor of the lathe and when tightened against the races of the wheel disc, provide a driving connection between the arbor and the disc and, in addition, align the disc with the axis of the arbor. Unless the adapters are precisely aligned with the arbor and the outer end faces of the adapters are perpendicular to the axis of the arbor, when the nut on the end of the arbor is tightened to clamp the brake disc between the adapters, two undesirable conditions occur. One, there is distortion in the nature of bending of the arbor, and, two, there is uneven pressure between the adapters and the brake disc or between the adapter and the nut. The former condition results in wobble and run-out during machining of the face of the disc, and the latter results in slippage of the disc relative to the arbor.

. An object of this invention is, therefore, to provide new and improved means for mounting a rotor such as a brake disc on the arbor of the lathe.

Another object of the present invention is to provide means for assuring proper alignment of the wheel disc and the arbor of the lathe.

A further object of the present invention is to and improved self-aligning spacer assembly.

Briefly, the above and further objects may be realized in accordance with the present invention by providing a pair of adapters for. clamping a brake disc or other rotor therebetween on the arbor of a lathe. One of these adapters engages the brake disc along a circular line while the other has a conical surface complementary to a precisely located conical surface within the hub of the disc. A self-aligning spacer is positioned between the latter adapter and the end nut on the arbor so that as the nut is tightened up the wheel disc is rigidly clamped between the adapters in alignment with the axis of the arbor. If the end face of the latter adapter is not precisely perpendicular to the axis of the arbor, due to the self-aligning nature of the spacer, 360 contact with the adjacent face of the adapter is nevertheless assured thereby preventing distortion of the arbor when the nut is tightened and also insuring good frictional contact between the adjacent adapter and the brake disc.

In one embodiment of the invention the spacer assembly in cludes a pair of sleeves, one of which tightly fits onto the arbor and the other of which has an internal diameter providing a clearance of about-0.050 inch or more with the arbor. The sleeves are held together by a resilient boot and have mutually abutting faces, one of which is spherical and the other of which is conical. For some applications the faces may be complementary spheres. The opposite end faces of the adapters are perpendicular to the axis of the bores therethrough.

Further objects and advantages and a better understanding of the present invention may be had by reference to the following detailed description taken in connection with the accompanying drawing wherein:

FIG. 1 is a fragmentary sectional view of a brake disc mounted on the arbor of a lathe by mounting apparatus embodying the present invention; and

FIGS. 2 and 3 are sectional views of a portion of the mounting apparatus of FIG. 1 but including a difi'erent spacer assembly embodying the present invention.

Referring now to the drawings and particularly to FIG. 1 thereof, there is shown an arbor connected to the spindle provide a new 12 of a lathe. An adapter 14 in the form of a sleeve has an internal diameter closely approximating the diameter of the arbor 10 so as to fit snugly thereon. The outer end face 18 of the adapter 14 is planar and perpendicular to the bore thereof so as to fit against the end face of the spindle 12. The wheel disc engaging surface 20 is annular and beveled so as to provide substantially line contact with a generally conical surface 22 of the wheel disc 24. The surface 22may be the outer race of the inner wheel bearing which supports the disc 24 on the axle of the automobile with which it is used. Consequently, the surface 22 is precisely located relative to the braking surfaces 26 and 28 of the wheel disc. The wheel disc 24 also has an outer wheel bearing which includes an outer bearing race 30 having a conicalsurface 32. As is well known by those skilled in the art, the conical surfaces 22 and 32 have the same axis and it lies perpendicular to the planes of the brake surfaces 26 and 28.

A second wheel adapter 34, also sleevelike in construction, has a bore 36 whose internal diameter approximates the diameter of the arbor 10 so as to fit snugly thereon. The adapter 34 has a conical surface 38 at one end which is complementary to the conical surface 32 thereby providing a large annular area of contact between the adapter 34 and the brake disc 24 when the disc is compressed between the adapters 14 and 34. It will be noted that the adapters l4 and 34 have similar brake disc engaging surfaces at the opposite ends thereof for accommodating brake discs of a different size.

A spacer assembly 40 engages the end surface or face 42 of the adapter 34 and a nut 44 is threaded onto the end of the arbor 10. It may be seen that when the nut 44 is tightened onto the arbor 10 a force is exerted through the spacer assembly 40 to compress the brake disc 24 between the adapters l4 and 34. While the wheel disc 24 may rock to some extent on the beveled surface 20 of the adapter 14 because of the line contact provided, no such movement is permitted between the engaging surfaces 32 and 38 on the race 30 and the adapter 34. Therefore, any misalignment of the surface 32 relative to the principal axis of the wheel disc 34 or any misalignment of the end surface 42 of the adapter 34 relative to the principal axis of the arbor 10 tends to result in an improper alignment of the braking surfaces 26 and 28 relative to the axis of the arbor 10. More particularly, if the nut 44 were to directly engage the face 42 of the adapter 34 and anything less than 360 contact were to be provided between the nut 44 and the adapter 34 or between the adapter 34 and the brake disc 24, as the nut 44 were tightened, the arbor 10 would be deflected. Even relatively small deflections of the arbor are intolerable since they result in substantial'wobble or run-out of the brake disc near the edges. These discs may have a radius of about 10 inches. Moreover, in order to effect maximum material removal from the surfaces 26 and 28 during machining and further to insure a smooth satisfactory braking surface it is important that no slippage be provided between the brake disc and the arbor 10. Should the contact between the adapter 34 and the wheel disc be substantially less than 360 or if the contact between the adapter 34 and the nut 44 be substantially less than 360 it has been found that slippage of the disc 24 on the arbor results.

In order to assure 360 contact between the adapter 34 and the wheel disc 24 the spacer assembly 40 includes a first sleeve 46 having a bore 48 approximating the size of the arbor 10 so as to fit snugly thereon anda sleeve 50 having a bore 52 exceeding the diameter of the arbor 10 by about 0.050 inch or more. The sleeve 46 has a planar end face 54 lying precisely perpendicular to the axis of the bore 48 therein and the sleeve 50 has an end face 56 which is planar and which is also perpendicular relative to the bore 52 therein. The sleeves 46 and 50 have abutting faces or seats 58 and 60 respectively. The face 58 is spherical and the face 60 is conical thereby to provide substantial line contact throughout a circle. A resilient boot or connector 62 maintains the sleeves 46 and 50 in assembled relationship. As shown, the boot 62 has a pair of end flanges 64 and 66 disposed within annular grooves 68 and 70 in the sleeves 46 and 50 respectively. During assembly, the

boot 62 is stretched over the sleeves and released so that it occupies the position as illustrated in the drawing. The boot 62 not only functions to maintain the sleeves in assembled relationship but it also prevents foreign matter from collecting in the space between the seats 58 and 60 and retains a lubricant such as grease in such space. If desired, a recess may be provided beneath the inner surface of the boot for holding a lubricant which may be inserted therein by means of a syringe and needle.

ln using the apparatus of the present invention as illustrated in FIG. 1 to mount the wheel disc 24 on the arbor 10, an adapter 14 having an outer diameter equal to the inner diameter of the race 22 is selected and placed on the arbor adjacent the spindle 12. The wheel disc 24 is then positioned on the arbor and an adapter 34 is placed over the arbor and positioned with its conical surface 38 engaging the inner conical surface 32 of the outer bearing race of the disc 24. The spacer 40 is then placed on the arbor and the nut 44 is tightened to clamp the wheel disc 24 between the adapters l4 and 34 and thus onto the arbor 10. Any misalignment of the adapter 34 is corrected by the self-aligning spacer assembly 40 so that it is impossible to distort or deflect the arbor 10 by tightening the nut 44 thereon. Moreover, 360 contact between the nut 44 and the spacer 40, between the spacer 40 and the adapter 34, and between the adapter 34 and the wheel disc 24 is ensured whereby slippage of the disc 24 during machining is prevented.

With reference to FIG. 1, it should be noted that the sleeve 50 having the oversize bore 52 therein must be adjacent to the adapter 34 to correct for any misalignment of the adapter 34 on the arbor 10. Accordingly, if the spacer assembly were inadvertently clamped on the arbor with the sleeve 46 in engagement with the adapter 34 no self-alignment would be provided and the machined surfaces 26 and 28 might be unsatisfactory. In order to avoid this possibility, in accordance with another feature of the present invention there is provided a spacer assembly 75 as illustrated in FIG. 2.

The spacer assembly 75 includes a first sleeve 77 having a bore 78 exceeding the diameter of the arbor 10 by about 0.050 inch or more and a second sleeve 79 identical to the sleeve 77. The sleeves 77 and 79 have spherical faces or seats 80 and 82 respectively which engage conical faces or seats 86 and 88 on a sleeve 84. The bore 90 of the sleeve 84 approximates the diameter of the arbor 10 so as to fit snugly thereon. Resilient means in the form of a rubber boot 92 maintains the sleeves 77, 84 and 79 in assembled relationship. More particularly, the boot 92 includes a pair of re-entrance annular flanges 94 and 96 at respective ends thereof which are received in annular grooves'in the sleeves 77 and 79. The

spacer 75 may thus be placed onto the arbor 10 with either end in engagement with the face 42 of the adapter 34 thereby eliminating any chance of error occasioned by improper positioning of the spacer assembly between the adapter 34 and the end nut 44.

While the present invention has been described in connec tion with particular embodiments thereof, it will be understood by those skilled in the art that many changes and modifications may be made without departing from the true spirit and scope of the present invention. Therefore, it is intended by the appended claims to cover all such changes and modifications which come within the true spirit and scope of this invention.

What is claimed is:

l. A spacer assembly adapted to be mounted on a shaft or rod, comprising a first sleeve element having an end face and an internal diameter for receiving said shaft or rod,

a second sleeve element having an end face and an internal diameter greater than that of said first sleeve element,

at least one of said end faces being spherical, and

elastomeric sleeve means circumscribing said sleeve elements and having at least one end secured in a groove in one of said sleeve elements for holding said sleeve elements in assembled relationship with said end faces in mutual abutment.

2. A spacer assembly as set forth in claim 1 further comprismg a third sleeve element having an end face and an internal diameter larger than the internal diameter of said first sleeve element,

said first sleeve element having another end face abutting said end face of said third sleeve element, and

at least one of said last-mentioned end faces being substantially spherical.

3. A spacer assembly as set forth in claim 2 wherein the other ends of said second and third sleeve elements are planar and lie perpendicular to the bores therein.

4. A spacer assembly as set forth in claim'2 wherein said end faces of said first sleeve element are conical, and

said end faces of said second and third sleeve elements are convex.

5. A spacer assembly as set forth in claim 2 wherein said second and third elements have annular grooves in the peripheral surfaces thereof, and

said elastomeric sleeve means has internal annular flanges at the distal ends thereof respectively disposed in said grooves. 

1. A spacer assembly adapted to be mounted on a shaft or rod, comprising a first sleeve element having an end face and an internal diameter for receiving said shaft or rod, a second sleeve element having an end face and an internal diameter greater than that of said first sleeve element, at least one of said end faces being spherical, and elastomeric sleeve means circumscribing said sleeve elements and having at least one end secured in a groove in one of said sleeve elements for holding said sleeve elements in assembled relationship with said end faces in mutual abutment.
 2. A spacer assembly as set forth in claim 1 further comprising a third sleeve element having an end face and an internal diameter larger than the internal diameter of said first sleeve element, said first sleeve element having another end face abutting said end face of said third sleeve element, and at least one of said last-mentioned end faces being substantially spherical.
 3. A spacer assembly as set forth in claim 2 wherein the other ends of said second and third sleeve elements are planar and lie perpendicular to the bores therein.
 4. A spacer assembly as set forth in claim 2 wherein said end faces of said first sleeve element are conical, and said end faces of said second and third sleeve elements are convex.
 5. A spacer assembly as set forth in claim 2 wherein said second and third elements have annular grooves in the peripheral surfaces thereof, and said elastomeric sleeve means has internal annular flanges at the distal ends thereof respectively disposed in said grooves. 